Re: Weather at National Schools

james.tidy@xxxxxxxxxxxxxx wrote:
On May 27, 6:55 pm, Ted van de Weteringe
<myfulln...@xxxxxxxxxxxxxxxxx> wrote:
Andr...@xxxxxxxxxxxxxx schreef:

http://www.oarsport.co.uk/products/wintech_video.php?video=bailing
I don't see how it can be an alternative to inbuilt buoyancy in any way.
Self-bailing requires a) bailers above the waterline (or valves that
limit the throughput) and b) forward speed (or acceleration actually).
Both mean that the boat must be floating relatively high and be rowable
by consequence. And still, on flat calm water (with good acceleration
each stroke) you're only losing 3 pounds (less than 1.5 litre) on each
stroke per your own video. In contrast, each wave in bad chop may easily
dump 50 litre into the boat.

I can see how it may be beneficial in some situations but as I said, it
is not an alternative to inbuilt buoyancy.

Thinking about the process of swamping, it's a vicious cycle- water
gets into boat, boat sits lower in the water, more water gets in, and
so on until the boat is swamped. Perhaps a benefit of the WinTech
design is that, by being able to evacuate the water in the boat, the
cycle is stopped or at least slowed. But I can see your point about
the volumes that are involved.

Another problem, though, that I can see with the design isn't just the
volume of water, but also the fact that water enters the boat at the
front but has to slosh right down to the back before being self-
bailed. It might be more effective if there were a way to bail from
closer towards the bows, apart from individual pumps which, in any
case, can't cope with too much water.

On a completely different note, of all the photographs I've seen, only
one coxswain actually has his lifejacket inflated. On a related note,
I'd like to think that I'd be mature enough, as a coxswain, to refuse
to boat in conditions that I believed were unsafe, or to wind down and
stop racing once the full scale problems of the conditions became
apparent. I've been looking at all the pictures, and asking myself
what I'd do; would I have the courage to say, to a het-up young crew
intent on racing, that they need to stop for their own (and my...)
safety?

It is important to separate in everyone's mind the entirely different functions of self-bailing & buoyancy. There being already a surfeit of confusion & at this emotive moment, let's avoid comments which may increase that confusion.

Self-bailing is a competitively advantageous feature. It works (by using a small amount of your energy) to continuously extract any water which is on board. That water burden is not just more weight to pull along but work is done to keep it sloshing around. That work is a continuous absorber of energy, your energy, which cannot therefore move the boat.

The Wintech system is fairly described by their literature. It works, as admitted, at a fairly modest rate. That rate does not remotely match the inflows some boats encountered this weekend. It would not keep an under-buoyant boat afloat in the conditions which sank those other boats.

There are self-bailing systems which have much higher capacity without compromising shell performance. They are trap-door 1-way valve devices, inserted flush into the bottom of the boat. They can suck water out of a racing eight at prodigious rates. They're used by some coastal clubs & I've never understood why they're never seen inland.

Buoyancy is a different matter altogether. Without doubt the Wintech products are fully buoyant &, as a long-time campaigner for full shell buoyancy, I very much welcome this. What buoyancy does is to ensure that, however sudden the influx of water (& an eight can go from doing fine to sunk in <30 secs), & whether you are moving or not, you will _not_ find yourself sitting in water up to or way beyond your crown jewels (another UK term for N.Americans to look up ;) ). So you will not end up in the drink, nor swimming for your life, nor losing body heat while hoping for rescue. Nor will your boat be in the least bit unserviceable or unrowable. Nor will it be overstressed by an unintended localised water burden.

Self-bailing is a design factor which should improve performance in rough conditions.

Full buoyancy is a feature which will not only enhance competitive performance but in extreme conditions will save lives & reduce the chance of personal injury & the loss or damage of boats.

All designs should incorporate both of these entirely distinct & unrelated features.

HTH
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: http://tinyurl.com/2tqujf
Email: carl@xxxxxxxxxxxxxxxxx Tel: +44(0)1932-570946 Fax: -563682
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)
.

Relevant Pages

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